Atom A and Atom B have the same number of protons and neutrons, but they do not have the same number of electrons. Which statement describes the atoms?

The atoms have the same chemical symbol.
The atoms have the same charge.
The atoms have different atomic numbers.
The atoms have different atomic masses.

Consider a file currently consisting of 200 blocks. assume that the file control block (and the index block in the case of indexed allocation) is already in memory. calculate how many disk i/o operations are required for contiguous, linked, and indexed (single-level) allocation strategies, for each of the conditions listed below. in the contiguous-allocation case, assume that there is not room to grow at the beginning but there is room to grow at the end. also assume that the block information to be added is stored in memory.